Probability of contamination from severe nuclear reactor accidents is higher than expected: study

May 22, 2012

This shows the global risk of radioactive contamination. The map shows the annual probability in percent of radioactive contamination by more than 40 kilobecquerels per square meter. In Western Europe the risk is around two percent per year. Credit: Daniel Kunkel, MPI for Chemistry, 2011

Catastrophic nuclear accidents such as the core meltdowns in Chernobyl and Fukushima are more likely to happen than previously assumed. Based on the operating hours of all civil nuclear reactors and the number of nuclear meltdowns that have occurred, scientists at the Max Planck Institute for Chemistry in Mainz have calculated that such events may occur once every 10 to 20 years (based on the current number of reactors)  some 200 times more often than estimated in the past.

The researchers also determined that, in the event of such a major accident, half of the radioactive caesium-137 would be spread over an area of more than 1,000 kilometres away from the nuclear reactor. Their results show that Western Europe is likely to be contaminated about once in 50 years by more than 40 kilobecquerel of caesium-137 per square meter. According to the International Atomic Energy Agency, an area is defined as being contaminated with radiation from this amount onwards. In view of their findings, the researchers call for an in-depth analysis and reassessment of the risks associated with nuclear power plants.

The reactor accident in Fukushima has fuelled the discussion about nuclear energy and triggered Germany's exit from their nuclear power program. It appears that the global risk of such a catastrophe is higher than previously thought, a result of a study carried out by a research team led by Jos Lelieveld, Director of the Max Planck Institute for Chemistry in Mainz: "After Fukushima, the prospect of such an incident occurring again came into question, and whether we can actually calculate the radioactive fallout using our atmospheric models." According to the results of the study, a nuclear meltdown in one of the reactors in operation worldwide is likely to occur once in 10 to 20 years. Currently, there are 440 nuclear reactors in operation, and 60 more are planned.

To determine the likelihood of a nuclear meltdown, the researchers applied a simple calculation. They divided the operating hours of all civilian nuclear reactors in the world, from the commissioning of the first up to the present, by the number of reactor meltdowns that have actually occurred. The total number of operating hours is 14,500 years, the number of reactor meltdowns comes to four  one in Chernobyl and three in Fukushima. This translates into one major accident, being defined according to the International Nuclear Event Scale (INES), every 3,625 years. Even if this result is conservatively rounded to one major accident every 5,000 reactor years, the risk is 200 times higher than the estimate for catastrophic, non-contained core meltdowns made by the U.S. Nuclear Regulatory Commission in 1990. The Mainz researchers did not distinguish ages and types of reactors, or whether they are located in regions of enhanced risks, for example by earthquakes. After all, nobody had anticipated the reactor catastrophe in Japan.

25 percent of the radioactive particles are transported further than 2,000 kilometres

Subsequently, the researchers determined the geographic distribution of radioactive gases and particles around a possible accident site using a computer model that describes the Earth's atmosphere. The model calculates meteorological conditions and flows, and also accounts for chemical reactions in the atmosphere. The model can compute the global distribution of trace gases, for example, and can also simulate the spreading of radioactive gases and particles. To approximate the radioactive contamination, the researchers calculated how the particles of radioactive caesium-137 (137Cs) disperse in the atmosphere, where they deposit on the earth's surface and in what quantities. The 137Cs isotope is a product of the nuclear fission of uranium. It has a half-life of 30 years and was one of the key elements in the radioactive contamination following the disasters of Chernobyl and Fukushima.

The computer simulations revealed that, on average, only eight percent of the 137Cs particles are expected to deposit within an area of 50 kilometres around the nuclear accident site. Around 50 percent of the particles would be deposited outside a radius of 1,000 kilometres, and around 25 percent would spread even further than 2,000 kilometres. These results underscore that reactor accidents are likely to cause radioactive contamination well beyond national borders.

The results of the dispersion calculations were combined with the likelihood of a nuclear meltdown and the actual density of reactors worldwide to calculate the current risk of radioactive contamination around the world. According to the International Atomic Energy Agency (IAEA), an area with more than 40 kilobecquerels of radioactivity per square meter is defined as contaminated.

The team in Mainz found that in Western Europe, where the density of reactors is particularly high, the contamination by more than 40 kilobecquerels per square meter is expected to occur once in about every 50 years. It appears that citizens in the densely populated southwestern part of Germany run the worldwide highest risk of radioactive contamination, associated with the numerous nuclear power plants situated near the borders between France, Belgium and Germany, and the dominant westerly wind direction.

If a single nuclear meltdown were to occur in Western Europe, around 28 million people on average would be affected by contamination of more than 40 kilobecquerels per square meter. This figure is even higher in southern Asia, due to the dense populations. A major nuclear accident there would affect around 34 million people, while in the eastern USA and in East Asia this would be 14 to 21 million people.

"Germany's exit from the nuclear energy program will reduce the national risk of radioactive contamination. However, an even stronger reduction would result if Germany's neighbours were to switch off their reactors," says Jos Lelieveld. "Not only do we need an in-depth and public analysis of the actual risks of nuclear accidents. In light of our findings I believe an internationally coordinated phasing out of nuclear energy should also be considered ", adds the atmospheric chemist.

On the theory that a driver who knows when a red light will turn green is more relaxed and aware, vehicle manufacturer Audi is unveiling this week in Las Vegas a technology that enables vehicles to "read" traffic signals ...

Wow, unscientific doesn't begin to describe this analysis, idiotic would be a better fit.

Their representative sample of meltdowns is Chernobyl, a reactor design no sane country would use for power generation, and 3 meltdowns at the same plant, all due to a single event, an earthquake combined with a tsunami. From that they extrapolate to all reactors on earth. You've got to be kidding.

A bigger logical flaw in this type of risk estimate is that the choice isn't between nuclear power and nothing. Its between nuclear power and some other generation source, which is most parts of the world means coal or natural gas. A useful analysis would be a comparison of the risk of nuclear power to the risk of the alternative (which includes the effects of climate change due to CO2 emissions).

THE WHOLE POINT IS THAT BAD REACTORS FAIL. So let's throw away the good ones too!? I don't think so.

Two things: Don't build reactors in tsunami/earthquake-prone areas. Build reactors with a lot more safety like in North America.

So using the same stats, of 1 major incident in the past 50 years (3 Mile Island), with somewhat limited exposure and improvements in reactors since, I'd say North America has a higher level of safety that expected. Even if you add in terrorism.

Its pretty bad/crazy policy to place these reactors in dense populated areas. A new strategy with better power lines would make it possible to move nuclear power farther away and also make better use of alternative power sources like wind and solarpower.

Its pretty bad/crazy policy to place these reactors in dense populated areas. A new strategy with better power lines would make it possible to move nuclear power farther away and also make better use of alternative power sources like wind and solarpower.

As electricity is not well transportable, it is natural that the reactors be there where there are consumers. Otherwise, they would be built in the middle of the Pacific Ocean or Atlantic or North Pole/South!

Its pretty bad/crazy policy to place these reactors in dense populated areas. A new strategy with better power lines would make it possible to move nuclear power farther away...

I think one point the article was trying to make is that you can't move a nuclear reactor far enough away to keep it from hitting populated areas and affecting large populations. Even if Germany shuts down all it's reactors, they're still in danger from all of the reactors east of them going super-critical because of the fallout patterns they calculated.

One hundred years from now, the decommissioned nuclear energy plants can serve as museums for school field trips. "This reactor you see in front of you, children, was of the type that nearly wiped out the entire human race." That is, if we're not wiped out beforehand.

A global economy of 15 billion people powered exclusively by nuclear power would require the construction of 200,000 new nuclear reactors.

"According to the results of the study, a nuclear meltdown in one of the reactors in operation worldwide is likely to occur once in 10 to 20 years. Currently, there are 440 nuclear reactors in operation, and 60 more are planned." - Article

Given a meltdown rate of 1 core melt every 20 years for 440 reactors, with 200,000 reactors, core melts would be expected every 16 days.

This presumes that reactors in the civilized nations of Chad and Afghanistan would be maintained to the same level of quality that existing western reactors have been maintained.

"Their representative sample of meltdowns is Chernobyl, a reactor design no sane country would use for power generation, and 3 meltdowns at the same plant, all due to a single event, an earthquake combined with a tsunami. From that they extrapolate to all reactors on earth. You've got to be kidding." - Pouf la Pouf

Chernobyl's reactor was a fine design. It worked reliably for years right up to the point where operator error caused it to explode.

With a world filled with 200,000 reactors. How do you intend to prevent similar events?

Molten salt thorium reactors (thorium 400 times more abundant than uranium - with a fraction of the half life - meltdown proof claimed - an already 50 year history) could eliminate almost all of these risks - and fill the alternative energy gap that keeps us from going off high carbon fuels - like petroleum and coal now while we work out cost reductions and storage for solar, wind and tide.

If it weren't so grim it would be funny, that these nuke proponents think the problem is about the quality of the reactor's manufacture, when in reality everything the Japanese engineer is superior to anything else.

So, on one hand we clearly have another full meltdown, even without Three Mile Island included and there could be many more like this, with no commercial containment structures in place.

I agree that the only scientifically correct answer is exactly 0! If it can happen, it will. The probability needs to be quite literally zero. Only when everyone on earth puts truth and life first we can then have zero. We need that sanity in all of our choices individually; each and every person will need healthy core ethics as all this technology advances. I have talked with many people that dont even believe truth exists. When we agree on truth, then we can have a great discussion. Those that dont should not be in a discussion turned debate, as they are not holding a full hand of cards.

I suspect any reasonable analysis would include the relative safety of the reactor designs. Later generation designs are orders of magnitude safer because they have provisions for automatic fail-safe cutoff in the event of the reactor losing power. Consider a reactor design in which the rods which control power being fixed, and the reactor itself being suspended. On power loss the reactor itself falls away from the control rods.

There are several designs of this type to pick from. The old style light water reactors should all be retired, and replaced with reactors of newer safer design.

"This reactor you see in front of you, children, was of the type that nearly wiped out the entire human race." -- You think a reactor melt down would end the human race? lol. You know meltdowns dont toss much- if any- shit in the atmo other than radiation. when plants go meltdown they dont esplode like a bomb. the biggest world-ending threat of bombs is the shit it puts in atmo which makes crops no longer alive.

secondly, to "I am sure they included the core melt at TMI as well.Why do you ignore it?"please see: "The total number of operating hours is 14,500 years, the number of reactor meltdowns comes to four one in Chernobyl and three in Fukushima." - the article

lastly- visit http://www.nrc.go...sle.html for a 2 paragraph summary of the tmi incident. tldr coolant pump shut down, nuke reactor shut down, preassure built in the containment vessil, preassure valve opened, then failed to shut, operators didnt have a warning of the

failure to shut so they, judging by the increased preassure, thought the coolant was TOO much, so they cut it. 95% design flaws in the safety, electrical and warning systems user emergency procedures. all 3 of the incidents in this article were due to negligence or poor planning. dont put nukes on a fault line. der.

if 1990 SUVS have a really high chance of flipping over does that mean my 2013 compact car also has a high chance of flipping?

because the wright brothers plane only flew a stones throw before it came back down does that mean my 757 is going to go down over the atlantic? give me a break.

Averaging across the history of aviation I have determined that if you travel more than a few times it is certain to kill you.I calculated this by using the data from all aircraft flights, from the Sopwith Camel to the 747, and the extraordinary mortality of first world war pilots where the life expectancy of the crew was 20 minutes with 100% of those on board dying extrapolated to 747s clearly shows that on every flight longer than 20 minutes all the 450 people on board are likely to die.

Come on, this is absurd even by the standards of the innumerate polemicists at Greenpeace.

The Chernobyl reactor was a graphite moderated reactor, a type which is not build in the wester world. And the japanese reactors - although certainly well build - were build on a earthquake prone area.

So, if you use standard western technology and avoid earth quake areas, you have ZERO 40 kBq/m2 events in more than 10 000 years of reactor operation. That's pretty damn good....

And before you start claiming what not, "Three mile island" didn't produce [1] more radiation exposure to the population in the immediate viscinity than what was allready present in the background radiation..

The reactor accident in Fukushima has fuelled the discussion about nuclear energy and triggered Germany's exit from their nuclear power program.

Not quite correct. Chernobyl had already triggered that. The exit by 2020 was already law long before Fukushima. Merkel (bought by the industry) and her conservatives overturned that law 3 months before Fukushima (and, of course, then re-overturned that 4 months later when faced with massive approval rating drops)

Their representative sample of meltdowns is Chernobyl, a reactor design no sane country would use for power generation

But which is a design most all old reactors are based on (and almost all reactors in the world are old).

which is most parts of the world means coal or natural gas.

Germany will have replaced all nuclear generating capacity with alternatives (non-coal/gas) by the time the last reactor goes offline. Germany isn't exactly known for sunny skies. If we can do this - everybody can.

@antialias:Excellent analysis on your part all around. However, the history of Fukushima is an object lesson on what happens when a culture that's based on unquestioning obedience uses a technology with an unproven safety record. This retired GE engineer spills the beans:

Currently there are 436 reactors in operation and every 10-20 years one goes boom in a big way. Even if 'new technology reactors' were 10 times safer this would still mean we'd get one to go boom from every 2 months to about every 2 years. I'm pretty certain that that would leave the world in a pretty desolate state in short order.

"10 times safer" is also wildly unrealistic, since the problems that caused reactors to go boom in the past were not technology related or of a magnitude where technology played only a small part). and until now only high tech countries had reactors. I'm not confident Burma, Ethiopia or Honduras would have stellar safety mechanisms in place.

Evacuating entire stretches of countryside and dumping an entire country into economic turmoil every few months? Is that what we 'currently do'? Somehow it doesn't feel like it.

And remember: up until now we got exceeedingly lucky. Fukushima mostly went out to sea, Lucense was only averted by sealing the mountain it was in, and Majak and Chernobyl were in the middle of nowhere (and still the latter caused the entire european economy to take a major hit)

No. A reactor catastrophe is not "no worse than what we currently do". In no way whatsoever.

10x safer is completely realistic

Human error or 'natural desaster' is not something you can make '10 times safer' against. (Try making something earthquake proof - and then proof it against earthquakes of 10 times the strength.) And the old reactors were already being updated constantly - so they already had the newest security tech.

So you are assuming what then? That the world will never reach a population of 15 billion or that the impoverished nations will never consume energy at current U.S. rates of consumption?

"I see. My numbers are right, it is your assumption of 10x energy consumption that is way off." - Shotman

Yes, according to OSN estimates, human population will level off in around 10-11 billion by 2100, and then actually starts to fall (as its already happening in the west). Fertility rates are sharply declining worldwide (yes, even in undeveloped and developing countries). There will most probably never be 15 billion humans on this planet. And keep in mind that mortality follows natality with 70 year delay.

Your second assumption, that they will all consume energy at US levels is also unfounded. Despite the advances, third world will probably remain third world for a long time. And when it finally develops, fertility rates and population will fall (demographic-economic paradox).

I see no reason why new reactor desings designed primarily for safety couldnt be orders of magnitude safer than old designs.

Beacuse - and let me type this slowly so you can understand this - We already design these things as well as we know how. Getting 10 times better in ANY part (earthquake, crash, operator error, etc.) is not possible unless you have some (and by some I mean roughly 10 million) bright ideas that thousands of engineers didn't have yet.

You're hopelessly naive about what people do in the real world. These things are designed as well as possible (and improved on a constant basis after being built).

Yes, it may very well save lifes and lead to less financial costs as compared to damage fossil fuels currently do.

Only by collapsing entire economies and making them not use any fossil fuels anymore.

Yes we do now, and so far, there was no accident with such newer designs.All accidents to date were with reactors designed in the 60s, when nuclear safety was in its infancy, and it was not a big priority.

Almost all the reactors studied are decades old. A.A said that they were designed with the best knowledge available...yes, best knowledge of 50 years ago (i don't suppose they worked out the designs, and built them instantly in the same year, do you?). Anyone who drives 50 years old cars day-in day-out will certainly know how unsafe they are compared to this year's crop. it is disingenuous to blame ALL cars by studying the statistics of only death traps on wheels! Therefore, the study should have said: "Probability of contamination from severe nuclear reactor accidents, OF MUSEUM-GRADE ANTIQUE REACTORS DESIGNED 40 YEARS AGO is higher than latest designed reactors."

What is the source of the 18bn/reactor cost you quoted?If the anti-nukers have not impeded the developments and implementations of newer, safer reactors through delays and court proceedings, if every country that have decent engineers can built them cheaply, would market competition keep them obsolete and expensive?Steam boilers blew up when they were first used; early air crafts were dropping like flies. Why didn't we go back to walking, just to be absolutely safe? Why don't people stick with the earliest PCs that costs 10,000, 128k memory and 8Mhz CPU? Why all the drive for something better and cheaper? Why do you ditched the $100 Made In Japan CDR for a $10 Made in China one that does better?By global obstructive efforts to keep dangerous, obsolete designs with no improvements, replacement costs are made to be unacceptable. This maximizes profits, control, monopoly on nuclear tech, and denies adversaries' advancements in the field.

(cont.)The present Iran-Israel tussle is a laughable, transparent power play case in point. Who cares if Iran's clerics are nutcases or not, the real thrust of Israel's demands is a complete dismantling of Iran's nuclear tech, anything that has a "nuclear" tag associated with it. Period. Any nitwit can see it.So the rest of the world's rabble billions' hope of better, safer nuclear power for cheaper energy is strangled by this sort of political calculations for the control of this plentiful power, the greatest so far, since having the biggest stick to whack another hominid's heads. No wonder nuclear power is demonized, and restricted to the selected few. Plentiful, cheap power for the masses, and advancement of the human race be f&*cked! We are the alpha monkeys, f**ck the rest!

No, we will get 20 000 * (11/8) = 27 500 reactors. In reality it would be less, since current population boom is in third world countries with far less per capita energy consumption than in the west. Populations in countries with high energy consumption are declining.

Besides, this is all exercise in futility, since modern and future reactors could very well be so safe that 200 000 or even 500 000 wont be a problem. The conclusion of the study is flawed, since it compares apples and oranges (it assumes safety of the reactors designed in the 60s is the same as safety of those designed in 2000s). This is a ridiculous assumption.

A question for you: Whats the alternative? If we assume that our energy consumption would increase 10x as you claim (150 TW = 200 000 reactors needed), then what other energy source than nuclear would be even remotely able to satisfy such demand?If its true, it seems to be an argument for nuclear energy, not against it.

This is easy to say after Chernobyl disaster, but this design was considered inherently safe and quite widespread in the 1984. The Russians just forget the samarium poisoning and graphite annealing due the Wigner effect. The same could be said about design of Fukushima plant, which was found quite vulnerable against flooding recently. For example, we have many nuclear plants in our country, which are dependent to the electric source in their cooling. This electric source is quite vulnerable to the earthquakes and it should be equipped with backup to avoid the situation, when the main plant generators will not be able to work anymore.

That is a good question, since building 200,000 nuclear reactors is not feasible, only a fraction can be built. Let's assume 10% of them could potentially be built.

That means that energy consumption per-capita in the U.S. must fall to 10 percent of the current value, if there is to be global energy equity.

"If we assume that our energy consumption would increase 10x as you claim (150 TW = 200 000 reactors needed), then what other energy source than nuclear would be even remotely able to satisfy such demand?" - ShotMan

The present Iran-Israel tussle is a laughable, transparent power play case in point...the real thrust of Israel's demands is a complete dismantling of Iran's nuclear tech, anything that has a "nuclear" tag associated with it. Period. Any nitwit can see it...the rest of the world's rabble billions' hope of better, safer nuclear power for cheaper energy is strangled by this sort of political calculations for the control of this plentiful power

Ahh, the global conspiracy to stop everyone from getting safe, cheap, and easy nuclear power! I was wondering if I'd hear that again this decade.

Nobody cares if Iran has nuclear power, which only requires ~4% enriched uranium. What they care about is whether Iran is progressing towards the ability to enrich sufficient quantities over 90% to build a nuclear weapon. There is absolutely no doubt that their current enrichment capability exceeds civilian power requirements. The debate is whether they are seeking weapons or a breakout capability

... the global conspiracyobody cares if Iran has nuclear power, which only requires ~4% enriched uranium. What they care about is whether Iran is progressing towards the ability to enrich sufficient quantities over 90% to build a nuclear weapon...

Thanks for the head up: "Allegations of nukes more valid than existing nukes, this is current gold standard of truth and integrity, how to judge and behave. " Applying your "gold standard of logic", I simply declare you are an allegedly untrustworthy, lying bastard, not fit to let to procreate responsibly , even with supervision. I should sleep with your wife and not you. you are already guilty, I have my own gang of witnesses. It's up to you to prove you are innocent, but then again I can always make new allegations, and have new witnesses, until you accept you are guilty as I wanted all along, and your wife is mine!. If you don't accept it, I'd punch your face in, or get my gang to do it. How do you like it, heh?

Beacuse - and let me type this slowly so you can understand this - We already design these things as well as we know how. Getting 10 times better in ANY part (earthquake, crash, operator error, etc.) is not possible unless you have some (and by some I mean roughly 10 million) bright ideas that thousands of engineers didn't have yet.

Hey I have an idea - let's not put critical electrical equipment like generators in the basements of tsunami-vulnerable facilities. Think that'll fly?

I highly doubt that we can bring down our energy consumption to 10% of today without significantly sacrificing quality of life. Efficiency just wont cut it, because its a classic example of a law of diminishing returns. It is a cherry on top, not the solution.

"That is a good question, since building 200,000 nuclear reactors is not feasible, only a fraction can be built. Let's assume 10% of them could potentially be built."

Why couldnt we build more than 10% of the 200 000 reactors? Contrary to renewables, nuclear reactors are not very limited by available land or specific places with favorable conditions. They are more like fossil power plants in this regard. We can just keep building more, until the demand is satisfied. This is especially true when talking about Gen IV small modular designs.There is no reason why one nuclear power plant facility cannot house 20 reactors, instead of 2/4/6 like its common now.

Hey I have an idea - let's not put critical electrical equipment like generators in the basements of tsunami-vulnerable facilities. Think that'll fly?

That won't do much good against large earthquakes. Electrical systems (and cooling systems) are large and finnicky. A rupture in any one line or pipe and that's all she wrote. Yes, you can make those resistant to earthquakes and build multiple backups - but only to a point. E.g. no one was prepared for a 9.0 magnitude quake. Design specs were for 7.6 or thereabouts. (One point on the Richter scale means 10 times the wave amplitude and 31 times the energy). If the epicenter is right underneath the plant then there is not much you could do to shield against such a quake. It would be like lifting the entire site up a few meters and dropping it.

It only wasn't a problem because the epicenter wasn't on site.The problem is that (as explained before) nuclear reactors need water. Which means ocean shores (tsunami risk) or rivers (which run in earthquake faults for the most part and are therefore earthquake prone sites by definition)

You can't just up the MTBF of a complex technical system above an arbitrary value. If we could then we'd already be doing it. There are just some things you don't think about beforehand (like where to put the backup generators). Hindsight is 20/20 - but you can bet there are other potential hazards that have been missed. Software isn't foolproof. Operator error is something that is so 'creative' that you can't design against it with absolute certainty. and then there are forces (landslides, plane crashes, earthquakes of a certain size ...) that you cannot control - no matter your design.

That won't do much good against large earthquakes. Electrical systems (and cooling systems) are large and finnicky. A rupture in any one line or pipe and blah

-Says the accomplished engineer. Those facilities were designed for 6.5 mag quakes. Engineers could have done better with stricter parameters and a willingness to spend more money. And the generators COULD have been placed in less vulnerable locations. Cost vs safety is always a tradeoff. Facilities are being modified from lessons learned and will be built to more stringent standards in the future.

Engineers could have done better with stricter parameters and a willingness to spend more money.

I think you VASTLY underestimate the effort to go from "Earthqualke-proof for Richter scale value x" to "Earthqualke-proof for Richter Scale x plus 1"10 times the size of the wave. 31 times the energy.

To go from 6.5 to 9.5 (the maximum possible estimated earth quake strength) we are talking a factor of a thousand(!) in wave height and about thirty thousand(!) in energy. This is not done with a 'bit more strict parameters and willingness to spend a little more money'. There are limits to engineering.

Facilities are being modified from lessons learned and will be built to more stringent standards in the future.

Guess what: Old facilities are also upgraded. So there is little difference between "best engineering of today" and the standard of old reactors.

There is only so much you can and do upgrade once the reactors and containment structures are build. Even with upgrades, 40 year old reactors are vastly below the standards of say, new AP-1000, which has multiple passive safety systems and 300% redundancies.

To go from 6.5 to 9.5 (the maximum possible estimated earth quake strength)

And I do not know what more prudent design parameters are being considered. Apparently they are working on it.

"TOKYO (Reuters) - Japan's parliament began a debate on Tuesday about plans for a new nuclear watchdog, raising hopes of a compromise after months of political bickering that has postponed a tightening of industry oversight after the Fukushima crisis.

The push to create a nuclear regulatory agency is part of Tokyo's efforts to allay public concerns about safety as it nears a decision on restarting some of its idled reactors, all of which have been shut down in the 14 months since Fukushima."

new AP-1000, which has multiple passive safety systems and 300% redundancies.

Newsflash: Old reactors have tripple redundant systems, too. But you know what the problem with redundant systems are? They are all vulnerable to the SAME systemic error. You could have 100 redundant emergency generators and a flood or an EMP or a big enough earthquake would take them all out.

Passive safety systems also require that the containment vessel stays intact (or that the pools where you keep the spent fuel stays intact). These are SYSTEMIC weaknesses. If the pool develops a crack and leaks then that's it - no matter how many redundant systems you have.

I think you really need to experience an earthquake or a tsunami or a plane crash to appreciate the forces involved. This is NOT an occurence when 'some stuff remains unaffected and can function as backup with certainty'.

If you don't accept it, I'd punch your face in, or get my gang to do it. How do you like it, heh?

Skepticus, I could refer you to a good therapist. There are many medications and treatments that may be able to help you.

I apologize if my post did not meet the high standards of academic rigor demonstrated by your post. Next time, I'll attempt to be less factual and more rapey.

My last response to you: If you can't take your own logic against you (regrettably how distasteful my example that may be) then you have no reason to be on a site of science and logic. If you subscribe to the "One rule for us, another for them", there is a category term for it: Thuggery. Have a good day.

AA, I respect your thoughtful posts throughout this site, and the expertise that lies behind it. As far as I understand, you are basically saying catastrophe is a multi-vectors damaging causes happen to a point/place/circuit/system; while a redundancy failure is a single cause that affects multiple redundant circuits. What are your thoughts on the case of 3 redundant hydraulic circuits for control of airplanes, that are physically running next to one another, as can be perused from airplane accident articles on wiki? Were the engineers who drafted such layout think that such proximity not an issue? To me, any redundancy circuit must fail under a completely different damaging vector, be it physical, spacial or loads as a minimum and designed and laid out as such. What say you?

My last response to you: If you can't take your own logic against you (regrettably how distasteful my example that may be) then you have no reason to be on a site of science and logic. If you subscribe to the "One rule for us, another for them", there is a category term for it: Thuggery. Have a good day.

There was no logic to your post, it was simply an incoherent, angry rant. It is truly astonishing that you think you have any basis for lecturing me on science. You obviously do not.

Since you clearly did not understand my post, I'll repeat myself in simpler terms. I did not make any policy proscriptions, say whether or not Iran is "allowed" to build nuclear weapons, or anything along those lines. I pointed out publicly available facts so we could avoid your emotional arguing: Iran's rapidly increasing enrichment capacity exceeds its requirements for civilian purposes. They are approaching weapons breakout capability. What to do about that? Separate discussion.

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